This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

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Upland cotton lint yield response to several soil moisture depletion levels was measured in 1997 and 1998. In 1997, four Upland cotton varieties including DP 5415, DP 33B, DP 5816, and STV 474 were tested. However because of a nonsignificant variety difference in the 1997 test, the 1998 test was planted to a single variety (DP 33B). In 1997 and 1998, depletion of plant available soil water (PAW) irrigation treatments consisted of 35%, 50%, 65%, and 80%. In 1997, all PAW depletion treatments were significantly different with the 35% PAW treatment resulting in the highest average lint yield of 1880 lbs. lint/acre. The 50%, 65%, and 80% PAW treatments resulted in 1410, 1123, and 248 lbs. lint/acre respectively. There was no significant (P<0.05) difference between varieties within all PAW treatments in 1997. In 1998, all PAW depletion treatments again were significantly different with the 35% PAW treatment resulting in the highest average lint yield of 1658 lbs. lint/acre. The 50%, 65%, and 80% PAW treatments resulted in 1534, 1396, and 641 lbs. lint/acre respectively.

This study uses a quadratic programming model to estimate impacts of Bt cotton adoption on consumer benefits, cotton program outlays, and producer returns, by state and by grower adoption status. Three scenarios were considered simulating low, moderate, and high impacts of Bt cotton adoption. For the moderate impact scenario, U.S. benefits from Bt cotton adoption grew from $44 million in 1996 to $66 million in 1998. Annual U.S. consumer benefits ranged from $46– $55 million. Benefits to Bt adopters grew from $57 million in 1996 to $97 million in 1998. Losses to non-adopters fell from -$59 million in 1996 to -$8 million in 1998 as rising commodity program payments countered the impact of lower prices. In 1998, gains to Arizona Bt cotton adopters (net of adoption costs) were about $9 million, averaging over $15,000 per adopting farm.

Gaining greater access to export markets, particularly Asian markets, is important to Arizona cotton producers. Over 80 percent of Arizona’s cotton shipments are exports, roughly double the U.S. average. Asian countries typically account for half of world cotton imports. Relative to the rest of the United States, Arizona (along with California) has a location advantage supplying these markets. In November 1999 the United States and China signed a trade agreement to reduce China’s trade barriers and win U.S. support for China’s entry into the World Trade Organization (WTO). According to recent USDA projections, the agreement would increase China’s net cotton imports by $359 million when fully implemented in 2005 and by $328 million per year between 2000-09. Political uncertainty surrounds the timing of China’s accession to the WTO, however, and China’s return to cotton net-importer status could be delayed by Chinese policies to draw down their large accumulation of cotton stocks.

Another year of data was collected to determine the effects of high frequency irrigation on irrigation uniformity in cotton production. A field located at the Marana Agricultural Center was split into two treatments. Treatment one was irrigated at approximately 35% depletion of available water in the plant rootzone. Treatment two was irrigated at approximately 65% depletion in the crop rootzone. Increased frequency of irrigation has shown improved yields in many cotton studies. However, these more frequent and lighter irrigation applications may cause problems with irrigation uniformity. Frequent rains during critical time periods made it difficult to ascertain the impact of the irrigation schedule on uniformity. However, the less frequent, heavier application rate did result in a more uniform irrigation.

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